Polycystic ovary syndrome (PCOS) in women is characterized by anovulation, LH hypersecretion, hyperandrogenism and insulin resistance. As the most common endocrinopathy in females, affecting 4-7% of reproductive-aged women, and as a frequent cause of infertility, accounting for 75% of anovulation, PCOS has staggering adverse physiological, psychological and financial consequence on reproduction in women. During gonadotropin stimulation for in vitro fertilization (IVF), PCOS women experience decreased fecundity and increased pregnancy loss. Since experimental investigation of oocyte and embryo development in humans is limited by ethical constraints, we have developed the prenatally androgenized (PA) female rhesus monkey as a model for PCOS. PA female monkeys undergoing follicle stimulating hormone (FSH) therapy for IVF exhibit LH hypersecretion, circulating insulin excess, an exaggerated shift in intrafollicular steroidogenesis from estradiol (E2) and androstenedione (A4) to progesterone (P4), and impaired embryo development beginning with embryonic genome activation. Because insulin enhances FSH-induced granulose cell differentiation, leading to LH-induced P4 production, we hypothesize that a) premature follicle luteinization and b) impaired oocyte developmental competence in PA monkeys are caused by adverse effects of hyperinsulinemia on follicle maturation. We predict that such abnormalities in PA monkeys are reversed by improved insulin sensitivity from weight loss through dietary restriction and will test our prediction in Specific Aims 1 and 2. Based upon data from our recognized nonhuman primate model of PCOS, we also hypothesize that c) premature follicle luteinization is a cause of poor oocyte developmental competence in PCOS women undergoing FSH therapy for IVF. We predict that granulosa cell dysregulation of LH receptor, insulin receptor (IR) and growth differentiation factor-9 (GDF-9) transcription from premature follicle luteinization causes poor cumulus cell proliferation in PCOS women (Specific Aim 3). We further hypothesize that d) meiotically-competent and meiotically-incompetent oocytes of PCOS patients are impaired in expression of GDF-9 and other developmentally relevant messenger ribonucleic acids (mRNAs) (Specific Aim 4). The long-term objectives of this proposal are to: 1) define molecular markers of oocyte developmental competence that enhance IVF pregnancy outcome by improving rates of embryo cleavage and blastocyst formation; while minimizing pregnancy loss in women with PCOS and other insulin resistant states, such as obesity and Type II diabetes, and 2) to provide additional, unique, insight into the transgenerational effect of PCOS.